docs: def set_operator(self, operator):
          """Set the current :ref:`OPERATOR`
          to be used for all drawing operations.
  
          The default operator is :obj:`OVER <OPERATOR_OVER>`.
  
          :param operator: A :ref:`OPERATOR` string.
  
          """
          cairo.cairo_set_operator(self._pointer, operator)
          self._check_status()